Australia's Top Renewable Energy Shares Leading the Clean Energy Revolution in 2025

The global pivot toward sustainable energy is accelerating, and Australia’s publicly listed companies are positioning themselves at the forefront of this transformation. With the shifting political landscape in the United States, Australian renewable energy shares and cleantech enterprises are capturing growing investor attention. Deloitte researchers anticipate Australia will secure approximately AU$123 billion in clean technology investments, fueled by emerging supply chain opportunities identified through the Net Zero Policy Lab’s comprehensive analysis.

The renewable energy sector—encompassing clean technology innovations, low-emission solutions, water management systems and waste optimization—presents compelling opportunities for those tracking ASX-listed sustainability leaders. Below is an examination of 10 major ASX cleantech and renewable energy companies, ranked by market capitalization as of May 5, 2025.

1. Rio Tinto (ASX:RIO, NYSE:RIO, LSE:RIO)

This mining powerhouse commands a market valuation of AU$159.48 billion with shares trading at AU$115.59. Rio Tinto has become instrumental to the cleantech supply chain through its dominant positions in copper, lithium and aluminum production—all critical commodities for renewable energy infrastructure and battery technology.

The company’s strategic commitment to decarbonization is exemplified through the ELYSIS joint venture, which has pioneered greenhouse gas-free aluminum smelting technology. Rio Tinto’s Arvida facility in Québec, Canada, will be the first to commercially produce this revolutionary environmental product. Complementing this innovation, Rio Tinto’s March 2025 acquisition of Arcadium Lithium directly integrates the company into electric vehicle and battery supply chains, strengthening its role in the global energy transition.

2. Meridian Energy (ASX:MEZ, OTC Pink:MDDNF)

Carrying a market cap of AU$13.93 billion with shares at AU$5.11, Meridian Energy operates as New Zealand’s largest electricity generating enterprise. The company’s renewable energy portfolio includes five wind installations, seven hydroelectric stations and utility-scale solar operations.

Recent milestones demonstrate Meridian’s expansion trajectory. The Harapaki wind farm reached operational status in July 2024, now ranking as New Zealand’s second-most productive wind facility. Notably, Meridian also developed and operates the Ross Island wind installation located in Antarctica, underscoring the company’s technical expertise in challenging environments.

3. Reece (ASX:REH, OTC Pink:REECF)

Trading at AU$16.16 per share with a AU$10.48 billion market capitalization, Reece functions as a global distribution leader for plumbing, water systems and HVAC-R components across Australia, New Zealand and the United States. The company’s contribution to sustainability extends through the Reece Foundation’s initiatives connecting the trades industry with communities requiring access to clean water and sanitation infrastructure.

4. Mercury (ASX:MCY, OTC Pink:MGHTF)

Mercury’s valuation stands at AU$7.65 billion with a share price of AU$5.27. This New Zealand utility generates electricity through diversified renewable sources—wind, hydroelectric and geothermal power. The company’s nine hydroelectric stations collectively provide approximately 10 percent of New Zealand’s annual electricity needs, while five geothermal facilities and four wind farms round out its generation portfolio. Construction of an additional wind farm is projected to conclude by the end of 2026, further expanding Mercury’s renewable energy capacity.

5. Contact Energy (ASX:CEN, OTC Pink:COENF)

With a market cap of AU$6.78 billion and share price of AU$7.89, Contact Energy supplies electricity, natural gas, broadband, solar and renewable generation services. The enterprise operates 11 power stations producing between 80 and 85 percent of its electricity from renewable hydro and geothermal sources.

Contact Energy’s commitment to decarbonization gained recognition through its inclusion in the 2023 Dow Jones Sustainability Index Asia-Pacific and its receipt of Deloitte’s 2023 sustainability leadership award. The company’s Contact26 strategy channels more than NZ$1.2 billion toward renewable generation investments, including its new 101 megawatt Te Mihi Stage 2 facility, anticipated to commence operations in Q3 2027.

6. Cleanaway Waste Management (ASX:CWY, OTC Pink:TSPCF)

Valued at AU$5.87 billion with shares at AU$2.64, Cleanaway Waste stands among Australia’s largest waste management operators. The company specializes in comprehensive e-waste recycling through 250 nationwide facilities, positioning it as a critical player addressing Australia’s plastic waste crisis and achieving waste self-sufficiency following China’s 2021 recycling material embargo.

7. Pilbara Minerals (ASX:PLS, OTC Pink:PILBF)

This enterprise carries a market capitalization of AU$4.76 billion with a AU$1.48 share price, establishing itself as one of Australia’s premier lithium producers. The Pilgangoora project in Western Australia’s Pilbara region represents the company’s flagship asset, yielding spodumene and tantalite concentrate essential for battery and renewable energy technologies.

The P1000 expansion initiative achieved ahead-of-schedule completion, reaching first ore production in January 2025. Pilbara Minerals maintains long-term supply agreements with prominent international players including China’s Ganfeng Lithium, Great Wall Motor Company, Yibin Tianyi and General Lithium, solidifying its position within global battery supply networks.

8. Reliance Worldwide (ASX:RWC, OTC Pink:RLLWF)

Capitalized at AU$3.2 billion with shares trading at AU$4.09, Reliance Worldwide engineers and manufactures high-efficiency water management and control systems. The company’s specialization in push-to-connect plumbing technology serves markets across the Americas, Asia-Pacific, Europe, the Middle East and Africa through 29 distribution centers, 14 manufacturing facilities and five research innovation hubs.

9. Sims (ASX:SGM, OTC Pink:SMUPF)

Sims maintains a AU$2.86 billion market valuation with shares at AU$14.78. Through its Sims Metal division, the company has embedded itself within the circular economy by processing and recycling scrap metals—both ferrous and non-ferrous varieties—across more than 130 facilities spanning the United States, United Kingdom and Australasia.

10. Nanosonics (ASX:NAN, OTC Pink:NNCSF)

Valued at AU$1.48 billion with a AU$4.73 share price, Nanosonics specializes in infection prevention through proprietary automated disinfection technology. The company’s Trophon device employs ultrasound technology for high-level probe disinfection, primarily serving hospital systems. The disinfection process converts residual chemicals into benign oxygen and water compounds.

Nanosonics is advancing its market reach with CORIS, an innovative endoscope reprocessing platform designed to address flexible endoscope reprocessing challenges. The US Food and Drug Administration approved CORIS in March 2025, marking a significant regulatory milestone.

This represents an updated analysis of ASX renewable energy and cleantech equities, building on research originally conducted in 2019.

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**Disclosure: I, Meagen Seatter, maintain no direct shareholdings in any company referenced._

**Disclosure: I, Melissa Pistilli, maintain no direct shareholdings in any company referenced._

The perspectives presented represent the author’s analysis and do not reflect the views of Nasdaq, Inc.